JP4329565B2 - Crimped yarn and fiber structure with excellent heat resistance - Google Patents

Description

The present invention relates to a composite fiber comprising an aliphatic polyester and a crystalline polyester having a melting point of 200 ° C. or more. More specifically, the present invention relates to applications requiring heat resistance and wear resistance, such as Y-shirts, blouses, and outerwear. The present invention relates to a crimped yarn composed of a core-sheath type composite fiber that can be suitably used as a clothing material.

  Recently, with increasing awareness of the environment on a global scale, the development of fiber materials that decompose in the natural environment is eagerly desired. For example, since conventional general-purpose plastics use petroleum resources as a main raw material, there are concerns that the petroleum resources will be depleted in the future, and global warming caused by mass consumption of petroleum resources has been taken up as major problems.

  For this reason, in recent years, research and development of various plastics and fibers such as aliphatic polyesters have been activated. Among them, attention is focused on plastics that are decomposed by microorganisms, that is, fibers using biodegradable plastics.

  Moreover, by using plant resources that grow by taking in carbon dioxide from the atmosphere, it can be expected that global warming can be suppressed by the circulation of carbon dioxide, and the problem of resource depletion may be solved. Therefore, attention has been focused on plastics starting from plant resources, that is, plastics using biomass.

  Until now, biodegradable plastics using biomass have not been used as general-purpose plastics due to their low mechanical properties and heat resistance, as well as high manufacturing costs. On the other hand, in recent years, polylactic acid using lactic acid obtained by fermentation of starch as a raw material has attracted attention as a biodegradable plastic having relatively high mechanical properties and heat resistance and low production cost.

  Polylactic acid has been used in the medical field for a long time as, for example, a surgical suture, but recently it has become competitive with other general-purpose plastics in terms of price due to improvements in mass production technology. For this reason, product development as a fiber has been activated.

  However, when polylactic acid is used as a general-purpose clothing fiber, it has several drawbacks compared to polyester and nylon fibers. Of these, it has been pointed out that heat resistance and wear resistance are low. In order to make up for these drawbacks, for example, it is conceivable to blend a plastic having excellent heat resistance and wear resistance such as nylon and polyester with polylactic acid. However, since these blended products cannot be uniformly blended, it has been difficult to stably fiberize them by melt spinning.

  In addition, some composite spinning with general-purpose plastics has been proposed as a method for improving the characteristics of polylactic acid fibers. For example, Patent Document 1 describes a composite fiber composed of a polyamide polymer and an aliphatic polyester. However, the purpose of the composite fiber is to reduce the amount of the aliphatic polyester component by alkali to provide a new function, and therefore the aliphatic polyester component is exposed on the fiber surface. Therefore, it did not have heat resistance and wear resistance that can withstand practical use for clothing.

  Patent Document 2 describes a composite fiber having an aromatic polyester as a core and an aliphatic polyester as a skin layer. The composite fiber is subjected to surface modification by reducing the amount of the aliphatic polyester forming the skin layer with an enzyme, thereby enabling a good texture. However, it was found that the modification by enzyme treatment does not improve both heat resistance and wear resistance, but rather tends to deteriorate.

Patent Document 3 describes a side-by-side or eccentric core-sheath type composite fiber of a polytrimethylene terephthalate component and a polylactic acid component. In the case of the eccentric core-sheath type composite fiber, the polylactic acid forming the core is coated with the high-melting point polytrimethylene terephthalate, so that it has better heat resistance than the conventional polylactic acid fiber. However, since the present application is a spiral crimped yarn using the difference in shrinkage between the core and sheath components, it has the disadvantage that wrinkles and wrinkles are likely to occur and the dimensional stability is poor. Thus, the composite interface is easily peeled off at the portion, and thus the coating strength is weak, and a product having sufficient heat resistance and wear resistance cannot be obtained.
JP 2000-54228 A JP 2000-136439 A JP 2003-82530 A

  The present invention is intended to solve the above-mentioned conventional problems, and has excellent mechanical properties and excellent process passability, and when used as a product, has excellent heat resistance and wear resistance. And a crimped yarn mainly composed of a biodegradable aliphatic polyester having bulkiness.

  The above object is a multifilament composed of core-sheath composite fibers of 3 filaments or more, wherein the thermoplastic resin forming the core part A of the core-sheath composite fiber is an aliphatic polyester, and the thermoplastic resin forming the sheath part B The film thickness of the crystalline polyester having a melting point of 200 ° C. or more and the crystalline polyester forming the sheath part B is 0.4 μm or more, and satisfies the following characteristics at the same time. Achieved by shrinking.

Expansion and contraction rate (CR): 10-50%
Boiling water shrinkage (SW): 2 to 20%

  The present invention has excellent mechanical properties, heat resistance, and wear resistance, so that it has excellent process passability in warping, weaving and other fabrics, and also has excellent heat resistance, wear resistance, and bulkiness as a product. It is possible to give sex.

  The aliphatic polyester forming the core A of the conjugate fiber of the present invention refers to a thermoplastic polymer in which aliphatic alkyl chains are linked by ester bonds, such as polylactic acid, polyhydroxybutyrate, polybutylene succin. Nate, polyglycolic acid, polycaprolactone and the like. Among these, as described above, polylactic acid is preferable in terms of mechanical properties, heat resistance, and production cost.

Here, polylactic acid is a polymer having — (O—CHCH ₃ —CO) n— as a repeating unit, and is obtained by polymerizing lactic acid or its oligomer. Since lactic acid has two types of optical isomers, D-lactic acid and L-lactic acid, the polymer is poly (D-lactic acid) consisting only of D isomer and poly (L-lactic acid) consisting only of L isomer, and There is polylactic acid consisting of both. The optical purity of D-lactic acid or L-lactic acid in polylactic acid is lowered, the crystallinity is lowered, and the melting point drop is increased. Therefore, the optical purity is preferably 90% or more in order to improve heat resistance. A more preferable optical purity is 93% or more, and a still more preferable optical purity is 97% or more. As described above, the optical purity has a strong correlation with the melting point. The optical purity is about 90%, the melting point is about 150 ° C., the optical purity is 93%, the melting point is about 160 ° C., the optical purity is 97%, and the melting point is about 170 ° C. It becomes.

  In addition to the system in which two types of optical isomers are simply mixed as described above, the two types of optical isomer polymers are blended and formed into fibers, and then subjected to a high temperature heat treatment at 140 ° C. or higher. A stereo complex in which a racemic crystal is formed is more preferable because the melting point can be dramatically increased.

  In addition, residual monomers such as lactide are present in polylactic acid, but these low molecular weight residues can cause staining abnormalities such as heating heater stains in the drawing and false twisting processes and dyed spots in the dyeing process. It becomes. Further, in order to promote the hydrolyzability of the fiber and reduce the durability, these low molecular weight residues are preferably 1% by weight or less, more preferably 0.5% by weight or less, and further preferably 0.2% by weight or less. It is.

  In addition, components other than lactic acid may be copolymerized within a range that does not impair the properties of polylactic acid. However, from the viewpoint of biomass utilization and biodegradability, the lactic acid monomer ratio in the polylactic acid fiber needs to be 50% by weight or more. The lactic acid monomer is preferably 75% by weight or more, more preferably 96% by weight or more. Also, a thermoplastic polymer other than polylactic acid may be blended. Furthermore, additives such as particles, flame retardants, antistatic agents, antioxidants and ultraviolet absorbers may be contained as modifiers. Further, the molecular weight of the polylactic acid polymer is preferably 50,000 to 350,000 in terms of weight average molecular weight, and a good balance between mechanical properties and moldability is preferred, and more preferably 100,000 to 250,000.

  The method for producing the polylactic acid of the present invention is not particularly limited. Specifically, the method disclosed in JP-A-6-65360 is exemplified. That is, a direct dehydration condensation method in which lactic acid is dehydrated and condensed as it is in the presence of an organic solvent and a catalyst. Further, it is a method of copolymerizing and transesterifying at least two kinds of homopolymers disclosed in JP-A-7-173266 in the presence of a polymerization catalyst. Furthermore, there is a method disclosed in US Pat. No. 2,703,316. That is, an indirect polymerization method in which lactic acid is once dehydrated to form a cyclic dimer and then subjected to ring-opening polymerization.

  The thermoplastic resin forming the sheath B of the conjugate fiber of the present invention needs to be a crystalline polyester having a melting point of 200 ° C. or higher. By setting the melting point of the sheath part to 200 ° C. or more and the thickness of the sheath part described later to 0.4 μm or more, the heat resistance of the fiber can be drastically improved. The crystalline polyester is, for example, a polyester composed of a dicarboxylic acid component and a glycol component. As the dicarboxylic acid component, terephthalic acid, isophthalic acid, phthalic acid, 2,6-naphthalenedicarboxylic acid, 1,4-naphthalenedicarboxylic acid, 1 , 5-naphthalenedicarboxylic acid, 4,4′diphenyldicarboxylic acid, 4,4′diphenyl ether dicarboxylic acid, 4,4′diphenylsulfone dicarboxylic acid, 5-sodium sulfoisophthalic acid and other aromatic dicarboxylic acid components, succinic acid, Aliphatic dicarboxylic acid components such as adipic acid, suberic acid, sebacic acid, dodecanedioic acid, dimer acid, and eicosandioic acid can be used. These acid components can be used alone or in combination of two or more. Also good. Examples of the glycol component include ethylene glycol, 1,3-propylene glycol, 1,2-propylene glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, , 6-hexanediol, 1,2-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, diethylene glycol, triethylene glycol, polyalkylene glycol, 2,2′bis (4′-β -Hydroxyethoxyphenyl) propane or the like can be used. These glycol components may be used alone or in combination of two or more. However, as described above, the melting point of the crystalline polyester is essential to be 200 ° C. or higher, and the melting point is preferably 205 to 260 ° C. in order to facilitate complex spinning with the core component. More preferably, it is 210-240 degreeC. Further, in order to improve wear resistance as well as heat resistance, polyethylene terephthalate (hereinafter referred to as PET), polytrimethylene terephthalate (hereinafter referred to as PTT), polybutylene terephthalate (hereinafter referred to as PET) among crystalline polyesters. It is preferable to use PBT). Among them, it is most preferable to use PTT because it is difficult to cause interface peeling with the aliphatic polyester forming the core and is excellent in durability against repeated bending. PTT has a property that it is difficult to store strain energy at the composite interface because it has excellent flexibility and elongation recovery in the longitudinal direction of the fiber. Furthermore, it is easy to impart high stretchability and bulkiness by false twisting, and since it can be dyed at low temperature, it has the advantage that it can be dyed without damaging aliphatic polyester that is generally easily hydrolyzed. .

  The crystalline polyester may be a homopolymer, but it is also preferable to blend an elastomer or a copolymerized polymer in order to impart flexibility to the polymer. Furthermore, you may contain additives, such as particle | grains, a flame retardant, an antistatic agent, an antioxidant, and an ultraviolet absorber. The melting point of the crystalline polyester in the present invention is the peak temperature of crystal melting in DSC measurement, and at the same time, it is determined whether or not it is crystalline by the presence or absence of the crystal melting peak.

  Moreover, it is preferable that a compatibilizing agent is contained in the core component and / or the sheath component in order to enhance the adhesiveness of the composite interface between the core portion and the sheath portion and suppress interfacial peeling. As the compatibilizing agent, a compound that is compatible with both the core component and the sheath component, or a compound that reacts with the ends of both the core and sheath components to form a crosslinked structure is preferably used. It is not a thing. For example, the former compatibilizer includes a surfactant copolymer having a portion similar in basic structure to the core / sheath components, a block copolymer, and the like. Moreover, as what forms a crosslinked structure, the epoxy compound which has an epoxy group in the both terminal, an oxazoline compound, an oxazine compound, those copolymers, a carbodiimide compound, those copolymers, etc. are mentioned. When using a cross-linking agent, the cross-linking agent is added to one or both of the core / sheath components, and the cross-linking agent reacts with the terminal groups of each component existing in the vicinity of the composite interface, thereby interfacial adhesion. Will improve. Further, when polylactic acid is used as the core component, the reaction active terminal of the oligomer is blocked, so that the reaction active terminal in the polylactic acid is inactivated, and hydrolysis of polylactic acid can be suppressed. The reaction active terminal has a hydroxyl group and a carboxyl group, and examples of compounds having excellent carboxyl group blocking properties include the following compounds. As an epoxy compound preferably used as the carboxyl group blocking agent of the present invention, a glycidyl ether compound, a glycidyl ester compound, a glycidyl amine compound, a glycidyl imide compound, and an alicyclic epoxy compound can be preferably used.

  Examples of glycidyl ether compounds include butyl glycidyl ether, stearyl glycidyl ether, allyl glycidyl ether, phenyl glycidyl ether, o-phenylphenyl glycidyl ether, ethylene oxide lauryl alcohol glycidyl ether, ethylene oxide phenol glycidyl ether, ethylene glycol diglycidyl ether, polyethylene glycol Diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, glycerol triglycidyl ether, trimethylolpropane trig Bisphenols such as sidyl ether, pentaerythritol polyglycidyl ether, 2,2-bis- (4-hydroxyphenyl) propane, 2,2-bis- (4-hydroxyphenyl) methane, bis (4-hydroxyphenyl) sulfone; Examples thereof include a bisphenol A diglycidyl ether type epoxy resin, a bisphenol F diglycidyl ether type epoxy resin, a bisphenol S diglycidyl ether type epoxy resin obtained from a condensation reaction with epichlorohydrin. Of these, bisphenol A diglycidyl ether type epoxy resins are preferred.

  Examples of glycidyl ester compounds include benzoic acid glycidyl ester, p-toluic acid glycidyl ester, cyclohexanecarboxylic acid glycidyl ester, stearic acid glycidyl ester, lauric acid glycidyl ester, palmitic acid glycidyl ester, versatic acid glycidyl ester, oleic acid glycidyl ester Ester, linoleic acid glycidyl ester, linolenic acid glycidyl ester, terephthalic acid diglycidyl ester, isophthalic acid diglycidyl ester, phthalic acid diglycidyl ester, naphthalene dicarboxylic acid diglycidyl ester, bibenzoic acid diglycidyl ester, methyl terephthalic acid diglycidyl ester , Hexahydrophthalic acid diglycidyl ester, tetrahydrophthalic acid diglycidyl ester, Hexane dicarboxylic acid diglycidyl ester, adipic acid diglycidyl ester, succinic acid diglycidyl ester, sebacic acid diglycidyl ester, dodecanedioic acid diglycidyl ester, octadecanedicarboxylic acid diglycidyl ester, trimellitic acid triglycidyl ester, pyromellitic acid tetra A glycidyl ester etc. can be mentioned. Of these, glycidyl benzoate and glycidyl versatate are preferred.

  Examples of glycidylamine compounds include tetraglycidylaminodiphenylmethane, triglycidyl-p-aminophenol, triglycidyl-m-aminophenol, diglycidylaniline, diglycidyltoluidine, tetraglycidylmetaxylenediamine, diglycidyltribromoaniline, tetra Examples thereof include glycidyl bisaminomethylcyclohexane, triglycidyl cyanurate, and triglycidyl isocyanurate.

  Examples of glycidylimide compounds include N-glycidylphthalimide, N-glycidyl-4-methylphthalimide, N-glycidyl-4,5-dimethylphthalimide, N-glycidyl-3-methylphthalimide, N-glycidyl-3,6- Dimethylphthalimide, N-glycidyl-4-ethoxyphthalimide, N-glycidyl-4-chlorophthalimide, N-glycidyl-4,5-dichlorophthalimide, N-glycidyl-3,4,5,6-tetrabromophthalimide, N -Glycidyl-4-n-butyl-5-bromophthalimide, N-glycidyl succinimide, N-glycidyl hexahydrophthalimide, N-glycidyl-1,2,3,6-tetrahydrophthalimide, N-glycidyl maleimide, N- Glycidyl-α, β-dimethyl Succinimide, N-glycidyl-α-ethylsuccinimide, N-glycidyl-α-propylsuccinimide, N-glycidylbenzamide, N-glycidyl-p-methylbenzamide, N-glycidylnaphthamide, N-glycidylsteramide, etc. be able to. Of these, N-glycidylphthalimide is preferable.

  Examples of alicyclic epoxy compounds include 3,4-epoxycyclohexylmethyl-3,4-epoxycyclohexylcarboxylate, bis (3,4-epoxycyclohexylmethyl) adipate, vinylcyclohexene diepoxide, N-methyl-4, 5-epoxycyclohexane-1,2-dicarboxylic imide, N-ethyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, N-phenyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide N-naphthyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, N-tolyl-3-methyl-4,5-epoxycyclohexane-1,2-dicarboxylic imide, and the like.

  Further, as other epoxy compounds, epoxy-modified fatty acid glycerides such as epoxidized soybean oil, epoxidized linseed oil, and epoxidized whale oil, phenol novolac type epoxy resins, cresol nozolac type epoxy resins, and the like can be used.

  Examples of the oxazoline compound preferably used as the carboxyl group blocking agent of the present invention include 2-methoxy-2-oxazoline, 2-ethoxy-2-oxazoline, 2-propoxy-2-oxazoline, 2-butoxy-2-oxazoline, 2-pentyloxy-2-oxazoline, 2-hexyloxy-2-oxazoline, 2-heptyloxy-2-oxazoline, 2-octyloxy-2-oxazoline, 2-nonyloxy-2-oxazoline, 2-decyloxy-2- Oxazoline, 2-cyclopentyloxy-2-oxazoline, 2-cyclohexyloxy-2-oxazoline, 2-allyloxy-2-oxazoline, 2-methallyloxy-2-oxazoline, 2-crotyloxy-2-oxazoline, 2-phenoxy- 2-oxa Phosphorus, 2-cresyl-2-oxazoline, 2-o-ethylphenoxy-2-oxazoline, 2-o-propylphenoxy-2-oxazoline, 2-o-phenylphenoxy-2-oxazoline, 2-m-ethylphenoxy- 2-oxazoline, 2-m-propylphenoxy-2-oxazoline, 2-p-phenylphenoxy-2-oxazoline, 2-methyl-2-oxazoline, 2-ethyl-2-oxazoline, 2-propyl-2-oxazoline, 2-butyl-2-oxazoline, 2-pentyl-2-oxazoline, 2-hexyl-2-oxazoline, 2-heptyl-2-oxazoline, 2-octyl-2-oxazoline, 2-nonyl-2-oxazoline, 2- Decyl-2-oxazoline, 2-cyclopentyl-2-oxazoline, 2-si Rohexyl-2-oxazoline, 2-allyl-2-oxazoline, 2-methallyl-2-oxazoline, 2-crotyl-2-oxazoline, 2-phenyl-2-oxazoline, 2-o-ethylphenyl-2-oxazoline, 2 -O-propylphenyl-2-oxazoline, 2-o-phenylphenyl-2-oxazoline, 2-m-ethylphenyl-2-oxazoline, 2-m-propylphenyl-2-oxazoline, 2-p-phenylphenyl- 2-oxazoline, 2,2'-bis (2-oxazoline), 2,2'-bis (4-methyl-2-oxazoline), 2,2'-bis (4,4'-dimethyl-2-oxazoline) 2,2'-bis (4-ethyl-2-oxazoline), 2,2'-bis (4,4'-diethyl-2-oxazoline), 2, 2'-bis (4-propyl-2-oxazoline), 2,2'-bis (4-butyl-2-oxazoline), 2,2'-bis (4-hexyl-2-oxazoline), 2,2 ' -Bis (4-phenyl-2-oxazoline), 2,2'-bis (4-cyclohexyl-2-oxazoline), 2,2'-bis (4-benzyl-2-oxazoline), 2,2'-p -Phenylenebis (2-oxazoline), 2,2'-m-phenylenebis (2-oxazoline), 2,2'-o-phenylenebis (2-oxazoline), 2,2'-p-phenylenebis (4 -Methyl-2-oxazoline), 2,2'-p-phenylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-m-phenylenebis (4-methyl-2-oxazoline), 2 , 2'-m-phenyle Bis (4,4′-dimethyl-2-oxazoline), 2,2′-ethylenebis (2-oxazoline), 2,2′-tetramethylenebis (2-oxazoline), 2,2′-hexamethylenebis ( 2-oxazoline), 2,2'-octamethylene bis (2-oxazoline), 2,2'-decamethylene bis (2-oxazoline), 2,2'-ethylenebis (4-methyl-2-oxazoline), 2,2'-tetramethylenebis (4,4'-dimethyl-2-oxazoline), 2,2'-9,9'-diphenoxyethanebis (2-oxazoline), 2,2'-cyclohexylenebis ( 2-oxazoline), 2,2'-diphenylenebis (2-oxazoline) and the like. Furthermore, the polyoxazoline compound etc. which contain the above-mentioned compound as a monomer unit can be mentioned.

  Examples of the oxazine compound that can be used in the carboxyl group blocking agent of the present invention include 2-methoxy-5,6-dihydro-4H-1,3-oxazine, 2-ethoxy-5,6-dihydro-4H-1. , 3-oxazine, 2-propoxy-5,6-dihydro-4H-1,3-oxazine, 2-butoxy-5,6-dihydro-4H-1,3-oxazine, 2-pentyloxy-5,6- Dihydro-4H-1,3-oxazine, 2-hexyloxy-5,6-dihydro-4H-1,3-oxazine, 2-heptyloxy-5,6-dihydro-4H-1,3-oxazine, 2- Octyloxy-5,6-dihydro-4H-1,3-oxazine, 2-nonyloxy-5,6-dihydro-4H-1,3-oxazine, 2-decyloxy-5,6-dihydro- H-1,3-oxazine, 2-cyclopentyloxy-5,6-dihydro-4H-1,3-oxazine, 2-cyclohexyloxy-5,6-dihydro-4H-1,3-oxazine, 2-allyloxy- 5,6-dihydro-4H-1,3-oxazine, 2-methallyloxy-5,6-dihydro-4H-1,3-oxazine, 2-crotyloxy-5,6-dihydro-4H-1,3- Oxazine and the like, and 2,2'-bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-methylenebis (5,6-dihydro-4H-1,3- Oxazine), 2,2'-ethylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-propylenebis (5,6-dihydro-4H-1,3-oxazine), 2 , 2'- Tylene bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-hexamethylene bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-p-phenylene bis (5,6-dihydro-4H-1,3-oxazine), 2,2'-m-phenylenebis (5,6-dihydro-4H-1,3-oxazine), 2,2'-naphthylenebis (5 6-dihydro-4H-1,3-oxazine), 2,2'-P, P'-diphenylenebis (5,6-dihydro-4H-1,3-oxazine) and the like. Furthermore, the polyoxazine compound etc. which contain an above-described compound as a monomer unit are mentioned.

  Among the oxazoline compounds and oxazine compounds, 2,2′-m-phenylenebis (2-oxazoline) and 2,2′-p-phenylenebis (2-oxazoline) are preferable.

  The carbodiimide compound preferably used as the compatibilizing agent of the present invention is a compound having at least one carbodiimide group represented by (—N═C═N—) in the molecule, for example, in the presence of a suitable catalyst. The organic isocyanate can be heated and produced by a decarboxylation reaction.

  Examples of carbodiimide compounds include diphenylcarbodiimide, di-cyclohexylcarbodiimide, di-2,6-dimethylphenylcarbodiimide, diisopropylcarbodiimide, dioctyldecylcarbodiimide, di-o-toluylcarbodiimide, di-p-toluylcarbodiimide, di-p- Nitrophenylcarbodiimide, di-p-aminophenylcarbodiimide, di-p-hydroxyphenylcarbodiimide, di-p-chlorophenylcarbodiimide, di-o-chlorophenylcarbodiimide, di-3,4-dichlorophenylcarbodiimide, di-2 , 5-dichlorophenylcarbodiimide, p-phenylene-bis-o-toluylcarbodiimide, p-phenylene-bis-dicyclohexylcarbodiimide, p-phenylene- Su-di-p-chlorophenylcarbodiimide, 2,6,2 ', 6'-tetraisopropyldiphenylcarbodiimide, hexamethylene-bis-cyclohexylcarbodiimide, ethylene-bis-diphenylcarbodiimide, ethylene-bis-dicyclohexylcarbodiimide, N , N′-di-o-triylcarbodiimide, N, N′-diphenylcarbodiimide, N, N′-dioctyldecylcarbodiimide, N, N′-di-2,6-dimethylphenylcarbodiimide, N-triyl-N ′ -Cyclohexylcarbodiimide, N, N'-di-2,6-diisopropylphenylcarbodiimide, N, N'-di-2,6-di-tert-butylphenylcarbodiimide, N-toluyl-N'-phenylcarbodiimide, N, N'-di-p-nitrophenyl Carbodiimide, N, N′-di-p-aminophenylcarbodiimide, N, N′-di-p-hydroxyphenylcarbodiimide, N, N′-di-cyclohexylcarbodiimide, N, N′-di-p-toluylcarbodiimide, N, N'-benzylcarbodiimide, N-octadecyl-N'-phenylcarbodiimide, N-benzyl-N'-phenylcarbodiimide, N-octadecyl-N'-tolylcarbodiimide, N-cyclohexyl-N'-tolylcarbodiimide, N- Phenyl-N'-tolylcarbodiimide, N-benzyl-N'-tolylcarbodiimide, N, N'-di-o-ethylphenylcarbodiimide, N, N'-di-p-ethylphenylcarbodiimide, N, N'-di -O-isopropylphenylcarbodiimide, N, N'-di p-isopropylphenylcarbodiimide, N, N'-di-o-isobutylphenylcarbodiimide, N, N'-di-p-isobutylphenylcarbodiimide, N, N'-di-2,6-diethylphenylcarbodiimide, N, N '-Di-2-ethyl-6-isopropylphenylcarbodiimide, N, N'-di-2-isobutyl-6-isopropylphenylcarbodiimide, N, N'-di-2,4,6-trimethylphenylcarbodiimide, N, Mono- or dicarbodiimide compounds such as N'-di-2,4,6-triisopropylphenylcarbodiimide, N, N'-di-2,4,6-triisobutylphenylcarbodiimide, poly (1,6-hexamethylenecarbodiimide) ), Poly (4,4'-methylenebiscyclohexylcarbodiimide), Poly (1,3-cyclohexylenecarbodiimide), poly (1,4-cyclohexylenecarbodiimide), poly (4,4'-diphenylmethanecarbodiimide), poly (3,3'-dimethyl-4,4'-diphenylmethanecarbodiimide) , Poly (naphthylene carbodiimide), poly (p-phenylene carbodiimide), poly (m-phenylene carbodiimide), poly (tolyl carbodiimide), poly (diisopropyl carbodiimide), poly (methyl-diisopropylphenylene carbodiimide), poly (triethylphenylene carbodiimide) ) And polycarbodiimides such as poly (triisopropylphenylenecarbodiimide). Among these, N, N′-di-2,6-diisopropylphenylcarbodiimide and 2,6,2 ′, 6′-tetraisopropyldiphenylcarbodiimide are preferable, and polycarbodiimide is preferable.

  As the carboxyl group blocking agent, one or more compounds can be arbitrarily selected and used.

  When a carboxyl group blocking agent is added, it is important to determine the carboxyl group terminal amount of the component to be added. Furthermore, since residual oligomers such as lactide also generate carboxyl group terminals by hydrolysis, the total carboxyl terminal amount including not only the carboxyl group terminals of the polymer but also those derived from the remaining oligomers and monomers is important. For example, when polycarbodiimide is used as the crosslinking agent, free polycarbodiimide compounds can be reduced by adding 1 to 5 times the total carboxyl end amount as the carbodiimide group equivalent of polycarbodiimide. Further, the interfacial adhesion can be remarkably improved by the crosslinked structure formed by blocking the carboxyl group ends of both the core and sheath components. The addition amount of the polycarbodiimide compound is more preferably 1.2 to 3 times the equivalent of the total carboxyl terminal amount, and still more preferably 1.3 to 2.5 times the equivalent.

  Further, the total carboxyl terminal concentration of the composite fiber is 20 equivalents / ton or less with respect to the whole fiber, and the hydrolysis resistance can be remarkably improved, and more preferably 10 equivalents / ton or less.

  Furthermore, a lubricant may be added to the crystalline polyester component in order to increase the lubricity in contact with the outside and improve the wear resistance. Lubricants include hydrocarbon waxes such as liquid paraffin, paraffin wax, micro wax and polyethylene wax, fatty acids such as stearic acid, 12-hydroxystearic acid and stearyl alcohol, higher alcohol waxes, stearamide and oleic acid. Amide lubricants such as amides, erucic acid amides, methylene bis stearic acid amides, ethylene bis stearic acid amides, ethylene bis oleic acid amides, ester waxes such as butyl stearate and monoglycerides of stearic acid, pentaerythritol tetrastearate, calcium stearate Metal soap such as zinc stearate, magnesium stearate or lead stearate can be applied. Of these, amide-based lubricants having a melting point of 100 ° C. or higher and excellent in external lubricity are preferred, and among them, fatty acid bisamides and alkyl-substituted fatty acid monoamides are most preferred. A plurality of these lubricants may be contained. The addition amount of the lubricant to the crystalline polyester is in the range of 0.05 to 5% by weight with respect to the crystalline polyester, and may be added in any of the polymerization step, drying, spinning step and the like.

  In the conjugate fiber constituting the crimped yarn of the present invention, it is important that the aliphatic polyester as the main component forms the core portion A and is covered with the crystalline polyester as the sheath portion B around the core portion A. Moreover, high heat resistance is acquired because the film thickness formed with crystalline polyester is 0.4 micrometer or more. There is a clear correlation between the film thickness of the crystalline polyester and the heat resistance, and the heat resistance improves as the film becomes thicker. Therefore, the film thickness of the crystalline polyester is preferably 0.6 μm or more, and more preferably 0.8 μm or more. More preferably, it is 1 μm or more. On the other hand, the upper limit of the film thickness is not particularly limited, but is preferably 10 μm or less in view of not impairing the characteristics of the aliphatic polyester. Further, the cross-sectional shape of the composite fiber may be any of a round cross-section, a polygon cross-section, a multi-leaf cross-section, a hollow cross-section, and other known cross-sections as long as it has a film thickness of 0.4 μm or more. In addition to a single core, a multi-core structure such as a 2-core or 3-core may be used. Examples of preferred cross-sectional shapes of the present invention are shown in FIGS. The coating thickness can be arbitrarily determined by the core-sheath composite ratio of the core part A and the sheath part B, the composite form, the discharge amount, the spinning speed, and the draw ratio, which are factors determining the fineness of the single fiber. it can.

  The crimped yarn of the present invention needs to have a stretch / restore rate (CR) of 10 to 50% based on a measurement method described later. By using a false twisted yarn with a CR of 10% or more, a product having high bulkiness, flexibility, and heat retention can be obtained when a fiber structure is formed. On the other hand, if the CR exceeds 50%, the texture tends to harden when the fiber structure is formed, and the surface quality tends to deteriorate. Therefore, CR is preferably 15 to 48% and more preferably 20 to 45% in order to impart bulkiness and stretchability as a processed yarn while providing a high-quality fabric surface.

  Moreover, it is preferable that the expansion-contraction elongation rate used as the parameter | index of the stretch property of a fiber is 15 to 100%. By setting it as this range, stretchability with high practicality can be imparted also as a fiber structure. The stretch / extension rate is more preferably 25% or more, and even more preferably 35% or more.

  The boiling water shrinkage of the crimped yarn of the present invention needs to be 2 to 20%. When the boiling water shrinkage is 2 to 20%, for example, when it is made into a woven fabric or a knitted fabric, a product having an excellent texture can be obtained without rough curing. Further, since shrinkage due to scouring or dyeing can be suppressed, the dimensional change is small, and the appearance as designed can be obtained. The boiling water shrinkage is preferably 3 to 16%, more preferably 4 to 12%.

  Further, the crimped yarn of the present invention preferably has a residual torque of 200 T / m or less. If the residual torque is 200 T / m or less, the warp of the yarn unwound from the cheese is suppressed and the running stability is excellent, so that the knitting and weaving properties are improved. Further, since the skew, weft, and streak of the resulting fiber structure can be suppressed, the quality of the high-quality final product is excellent. The residual torque is more preferably 150 T / m or less, and still more preferably 100 T / m or less. In addition, if the residual torque is 20 T / m or more, stable production is possible, and the influence on the quality of the final product is slight, which is preferable.

  Further, the crimped yarn of the present invention is liable to cause delayed shrinkage and yarn unevenness due to polymer characteristics when PTT or PBT is used as the sheath component. Therefore, the delay recovery rate is preferably 5% or less. When the delayed shrinkage is large, the drum package is deformed, so that the yarn in the inner layer portion of the package is pressed and the yarn is damaged. In addition, the occurrence of wrinkles, wrinkles, and dents is a cause of defects due to unevenness in the crimp characteristics in the longitudinal direction of the yarn. Similarly, after knitting and weaving, shrinkage occurs gradually, resulting in poor dimensional stability in the raw machine, and in some cases, a concentration of shrinkage stress causes a horizontal defect. In addition, in order to cause release tension unevenness of the yarn from the package, streaks and horizontal steps are generated in the case of a knitted fabric, and horizontal stripes are generated in the case of a woven fabric. In order to solve these problems, the delay recovery rate is more preferably 3% or less, and further preferably 2% or less.

  Although the method of lowering the delayed recovery rate will be described in detail later, it is effective to perform relaxation heat treatment with a 2nd heater after false twisting, or to perform relaxation treatment between the delivery roller and the winder.

  Further, the crimped yarn of the present invention receives external force in every process such as a weaving process such as beaming, weaving, and knitting. In order to suppress the exfoliation of the core-sheath composite interface and the generation of fluff caused thereby, it is preferable to attach a surface treatment agent mainly composed of a smoothing agent such as a fatty acid ester, mineral oil or polyether ester having a low friction coefficient. . By doing so, the process passage property in the said process can be improved significantly. The adhesion amount of the surface treatment agent may be appropriately changed depending on the processing method and application, but it is preferably about 0.2 to 2% of the adhesion amount with respect to the total fiber weight.

  Further, the mechanical properties of the crimped yarn of the present invention may be at a level that does not cause a problem in practice. For example, when used for a textile for clothing, a tensile strength of 1.5 cN / dtex or more, preferably 2 cN / dtex or more, More preferably, it is 2.5 cN / dtex or more, and the elongation may be 15 to 50%, preferably 18 to 45%, more preferably 20 to 40%.

  In addition, the crimped yarn of the present invention exhibits excellent performance with respect to high-temperature mechanical properties that are a problem with polylactic acid fibers. Usually, in the gluing drying performed after warping, drying is performed at a high temperature of about 80 ° C. while applying tension. At this time, the polylactic acid fiber has a problem that the tensile resistance at high temperature is small and the yarn extends. The crimped yarn of the present invention is coated with a crystalline polyester having excellent high-temperature mechanical properties, and therefore has excellent strength properties even under heating. The strength under heating at 90 ° C. is preferably 0.8 cN / dtex or more, and more preferably 1 cN / dtex. By the way, the strength of the fiber using 100% polylactic acid when heated at 90 ° C. is 0.3 cN / dtex at most.

  Further, the crimped yarn of the present invention preferably has 2% or less of Worcester plaque U%, which is an index of thickness variation in the fiber longitudinal direction. As a result, not only dyed spots on the fabric can be avoided, but also the shrinkage spots of the yarn when made into a fabric are suppressed, and a beautiful fabric surface is obtained. The Worcester plaque U% is more preferably 1.5% or less, further preferably 1% or less, and most preferably 0.6% or less.

  Further, if necessary, entanglement may be included, but if the CF value is too high, crimped spots are generated, and the quality is lowered when the fiber structure is formed. Therefore, the CF value is preferably 1 to 100, and more preferably 5 to 50. A more preferred CF value is 10-30.

  The crimped yarn is a multifilament composed of three or more fibers, but the crimped yarn of the present invention may be cut and used as a short fiber.

  In addition, the form of the fiber structure of the present invention may be a single crimped yarn, or mixed with other fibers to be used in clothing, knitted fabrics, nonwoven fabrics such as shirts, blousons, pants, cups, pads, boards, etc. Clothing materials, car seats, curtains, carpets, mats, furniture interiors, vehicle interiors, belts, nets, ropes, heavy cloths, bags, sewing threads, felts, non-woven fabrics, filters, artificial turf, etc. Includes various fiber product forms. When mixed with other fibers, synthetic fibers made of fiber-forming polymers such as polyester fibers, nylon fibers, acrylic fibers, vinylon fibers, polypropylene fibers, polyethylene fibers, regenerated fibers such as rayon, semi-synthetic materials such as acetate Fibers and natural fibers such as wool, silk, cotton and hemp are used. However, in order to make use of the characteristics of the aliphatic polyester, the content ratio of the present composite fiber is preferably 20% or more, and more preferably 50% or more.

  Moreover, the textile structure of this invention is used suitably for the textiles for clothes, the use which receives an iron press among them. The heat resistance of the fiber structure composed of the conjugate fiber of the present invention is preferably 160 ° C. or higher in the iron heat resistance test. By having a heat resistance of 160 ° C. or higher, it is possible to obtain a fiber structure that does not have a texture hardening or change in color tone even when ironing at low to medium temperatures. Here, the iron heat resistance test method will be described in detail.

For measurement, a commercially available iron is used, the iron surface temperature is stabilized to a desired temperature, and then the fabric is pressed for 10 seconds with the iron's own weight (surface pressure of about 8 g / cm ² ). . As a result of conducting an iron heat resistance test on a fabric composed of 100% polylactic acid fiber by the present inventors, the heat resistance of the polylactic acid fabric is at most about 120 ° C., and beyond that, the fiber is softened and flattened. A glossy spot called “around” occurs. Further, when the temperature of the iron is set to 150 ° C., a hole is formed due to partial melting, or a cloth with a strong feeling of coarseness is obtained, which is no longer practical. For this reason, it was impossible to apply a substantial iron when using 100% polylactic acid fiber. On the other hand, the woven fabric made of the crimped yarn of the present invention has a heat resistance of 160 ° C. or higher, and the softening and deformation of the fiber does not occur in a low to medium temperature iron, and there are no defects such as “around”. It is.

  Moreover, when using the fiber structure which consists of the crimped yarn of this invention regardless of the object for clothing and industrial materials, it is required to satisfy a practical level in various dyeing fastness tests determined by JIS. For example, when used for general apparel, a third or higher grade is required in terms of the fastness to dyeing for washing (JIS-L0844) and the fastness to dyeing for ultraviolet carbon arc lamp (JIS-L0842).

  As for the wear resistance which is the object of the present invention, it is preferable that both dryness and wetness are grade 3 or higher in the friction tester type II (Gakushin type) of the dyeing fastness test for friction (JIS-L0849). It is more preferable that both the dryness and the wetness are quaternary or higher. In addition, when the dyeing fastness test is carried out on a fabric made of 100% polylactic acid, the dyeing fastness to rubbing against the friction is very bad at the first grade for both dryness and wetness, although it passes the third grade in the washing and light resistance test.

  Here, the manufacturing method of the crimped yarn of this invention is demonstrated with figures.

  First, an aliphatic polyester that forms the core A and a crystalline polyester that forms the sheath B are selected from the polymers described above. For example, poly-L lactic acid having an optical purity of 97% (melting point: 170 ° C.) is used for the core part A, and PTT (melting point 228 ° C.) is used for the sheath part B. At this time, in order to highly orient the poly-L lactic acid in the core part on the spinning line and improve the mechanical properties of the fiber, it is necessary to make the weight average molecular weight of PTT lower than that of the poly-L lactic acid. The weight average molecular weight of PTT is preferably 1/2 to 1/5, more preferably 1/3 to 1/5 of the weight average molecular weight of poly-L-lactic acid. FIG. 3 is a schematic view of a spinning apparatus preferably used in the present invention. First, a polylactic acid chip charged in a hopper 1 is melted and extruded by an extruder 2 and the molten polymer is transferred to a spinning block 4. Similarly, the polytrimethylene terephthalate chip charged in the hopper 1 ′ is melted and extruded by the extruder 2 ′, and the molten polymer is phased on the spinning block 4. Further, the yarn is sent to a spinning pack 5 incorporated in the spinning block 4, and after filtering the polymer in the pack, the polymer is bonded to the core-sheath structure by the spinneret 6 and then discharged to obtain a yarn. The spun yarn is once cooled and solidified by the cooling device 7, and then an oil agent is applied by the oil supply guide 9, and is appropriately entangled by the entanglement device 10, then taken up by the godet rolls 11 and 12, and wound. It is wound up by the take-up machine 13. In addition, in order to remove the low melting point substance sublimated from the fiber, a suction device 8 is provided directly under the base. In addition, in order to suppress the precipitation of monomers and oligomers during spinning and to improve the spinnability, a 2-20 cm heating cylinder under the die, air for preventing polymer oxidation deterioration or die hole contamination, steam, N2 as necessary. Inert gas generators such as may be installed. The temperature of the spinning block is determined by the melting point of each core-sheath component on the high melting point side, but when PTT or PBT is used on the high melting point side, melt spinning may be performed at 240 to 255 ° C. Next, the film is stretched by a stretching machine and then false twisted or directly stretched by a false twisting machine. A method of false twisting after spin drawing in which spinning and drawing are continuously performed is also preferably used.

  When melt spinning, if the residence time during kneading and melt spinning is long, there is a problem that the polymer is colored due to thermal deterioration of the raw material polymer and the compatibilizing agent. Therefore, the shorter the residence time, the better, and preferably 30 minutes or less. In addition, the temperature of the molten polymer at this time is preferably as low as possible while ensuring fluidity. The residence time refers to the residence time from the melting of the polymer to the spinning, which includes the gap between the barrel and screw of the kneader, the specifications of the screw, the piping size between the kneader and the spin pack, the spin pack. It can be estimated from the dimensions inside. The residence time is more preferably 20 minutes or less, and even more preferably 15 minutes or less. Similarly, it is preferable to devise a method for adding a compatibilizing agent. The compatibilizing agent may be kneaded with the raw material polymer in advance, but it is preferable to add the compatibilizing agent directly during melt spinning in order to suppress the residence time. For example, when polylactic acid is melted in a kneader, the residence time in the melted state of the compatibilizer can be shortened by adding the compatibilizer while measuring with a side feeder or the like.

  It is important for the spinning oil agent to prevent contamination of the false twisting heater, prevent slippage with the twisted body (yarn threading property, increase the number of twists on the false twisting heater), and improve fiber migration within the multifilament. For this purpose, it is preferable to use an oil containing a smoothing agent having good heat resistance, a high fiber-twisted friction coefficient, and a low fiber-fiber friction coefficient. For example, a compound obtained by copolymerizing an alkylene oxide having 2 to 4 carbon atoms with an alcohol having one or more hydroxyl groups in the molecule and a compound derived therefrom are preferably used.

  As the alcohol, any natural or synthetic monohydric alcohol having 1 to 30 carbon atoms (methanol, ethanol, isopropanol, butanol, isoamyl alcohol, 2-ethylhexanol, lauryl alcohol, isotridecyl alcohol, isocetyl alcohol, stearyl alcohol) , Isostearyl alcohol, etc.), dihydric alcohols (ethylene glycol, propylene glycol, neopentyl glycol, hexylene glycol, etc.) and trihydric or higher alcohols (glycerin, trimethylolpropane, pentaerythritol, sorbitan, sorbitol, etc.). .

  The alkylene oxide having 2 to 4 carbon atoms includes ethylene oxide (hereinafter abbreviated as EO), 1,2-propylene oxide (hereinafter abbreviated as PO), 1,2-butylene oxide (hereinafter abbreviated as BO), tetrahydrofuran (hereinafter referred to as THF). Abbreviations). When EO is copolymerized with other alkylene oxide, the ratio of EO needs to be 50 to 80% by weight. If the EO ratio is less than 50% by weight, the viscosity becomes too high, and if it exceeds 80% by weight, the heat resistance becomes poor. The addition mode may be either random addition or block addition. The average molecular weight of the smoothing agent is preferably in the range of 500 to 20,000, more preferably in the range of 1,000 to 10,000 in terms of smoothness and heat resistance.

  The content of these smoothing agents is adjusted to 55% by weight or more based on the whole oil agent, and as other components, ionic surfactants, nonionic surfactants, bundling agents, rust preventives, antiseptics, antioxidants A paste property improver, an antistatic agent, a pH lowering inhibitor, and a water resistance agent may be added as appropriate.

  Moreover, it is preferable that the spinning oil agent is adhered to 0.1 to 3.0% by weight with respect to the whole fiber. The said characteristic is exhibited effectively by making the adhesion amount of an oil agent into 0.1 weight%. On the other hand, when the amount of the oil agent to be adhered exceeds 3% by weight, the false twisting heater, the roll, and the twisted body become very dirty. More preferably, it is 0.2-2.0 weight%, More preferably, it is 0.3-1.0 weight%.

  The oil agent preferably used in the present invention may be adhered straight to the yarn, but in order to adhere more uniformly, it is dispersed as 5 to 50% by weight in water, preferably 5 to 30% by weight, and the fiber is used as an emulsion oil agent. It is preferable to make it adhere to.

  The entanglement nozzle 11 may be installed on the spinning line as shown in FIG. 1, or may be installed between the godet rolls or before the winder. When it is desired to increase the degree of entanglement, it is preferably installed between godet rolls with low yarn tension or before the winder, and when it is desired to reduce the degree of entanglement, it is preferably installed on the spinning line.

  Moreover, in order to improve the adhesiveness of the core-sheath composite interface, the spinning speed (the peripheral speed of the first godet roll 12 in FIG. 3) is an important condition. The aliphatic polyester constituting the core part and the crystalline polyester constituting the sheath part have relatively good affinity, and the interfacial adhesion can be further improved by adding a compatibilizing agent. Furthermore, it has been found by the inventors' study that the adhesiveness is improved by increasing the spinning speed. Although this mechanism is not yet clear, thinning of the spun yarn occurs in a high-temperature region closer to the die surface by high-speed spinning, so that the difference in structural strain between the core-sheath components becomes smaller, and further, the stretch orientation This is considered to form a more stable fiber internal structure. Therefore, a preferable spinning speed is 2000 m / min or more, more preferably 2500 m / min or more, and still more preferably 3000 m / min or more. On the other hand, considering the process stability in spinning, the spinning speed is preferably 7000 m / min or less. By producing an undrawn yarn at a spinning speed in the above range, the elongation of the undrawn yarn is 40 to 180%, and it has good dyeability without causing interfacial peeling even when false twisting is performed. It can be a thread.

  In addition, when the PTT is used for the sheath B, the multifilament made of the conjugate fiber of the present invention relaxes (shrinks) the internal strain of the fiber, so when wound around a cheese-like package, a saddle (ear stand) or bulge ( Swelling) is likely to occur. When the saddle or bulge is large, not only the packaging of the package becomes complicated, but also the unraveling property is lowered and the process passability is lowered. Therefore, it is preferable to suppress the saddle to 6 mm or less and the bulge rate to 10% or less. More preferably, the saddle is 0 to 4 mm and the bulge rate is 0 to 6%.

  In order to eliminate saddles and bulges, it is necessary to remove the internal strain of the fiber between melt spinning and winding, and as a method for this, winding in a relaxed state is effective. Further, the winding tension at that time (the tension between the final godet roll and the winder) is preferably 0.04 cN / dtex or more in order to prevent reverse winding, in order to release the distortion of the fiber internal structure. Is preferably 0.15 cN / dtex or less. A more preferable winding tension is 0.05 to 0.12 cN / dtex, and further preferably 0.06 to 0.1 cN / dtex. Moreover, it is preferable to make the load with respect to the line length which a roller bail or a drive roll is contacting the package (equivalent to the pressure with respect to a package. Hereinafter, it is called a surface pressure) into the range of 6-30 kg / m. By setting the surface pressure to 6 kg / m or more, an appropriate hardness can be given to the package, and package collapse and saddle can be suppressed. Further, by making the surface pressure 30 kg / m or less, the package can be prevented from being crushed or bulged. A more preferable range is 7 to 22 kg / m, and further preferably 8 to 16 kg / m. In addition, by setting the twill angle in the range of 5 to 10 °, it is possible to obtain a stable unwinding tension even at high speed unwinding and to prevent the yarn from collapsing to the end surface while suppressing the yarn dropping on the package end surface. Can do. More preferably, it is 5.5 to 8 °, and further preferably 5.8 to 7 °. It is also important to change the twill angle to suppress the ribbon. As a means for this, it is preferable that the traverse angle is oscillated within a certain range (within the center value ± 1.5 °) or the wind ratio (ratio between the spindle rotation speed and the traverse cycle) is made constant. Further, a method of rapidly changing the twill angle in the ribbon generation zone region is also preferably used, and these methods may be combined. In general, since aliphatic polyester has low bending rigidity and strong behavior as an elastic body, it is necessary to devise a way to sufficiently follow the yarn when turning back during traverse. For this reason, a 1- to 3-axis blade traverse method with high-speed followability, a microcam traverse with good thread gripping properties, and a spindle traverse capable of shortening the free length are preferably used. Taking advantage of each characteristic, it is more preferable to use the microcam traverse method at a winding speed of 2000 to 4000 m / min, and to use a 1-axis to 3-axis blade traverse system when the winding speed exceeds 4000 m / min.

  The drive system at the time of winding is generally driven by a drive roller, but a spindle driving system and a method of forcibly driving a roller bail of the winder are preferably used. When the roller bail is forcibly driven, the roll bail speed relative to the package surface speed is controlled so as to always overfeed 0.05 to 1%, whereby the package foam can be improved.

  Next, a preferred false twisting method will be described with reference to FIG. First, the yarn 15 is pulled out from the cheese 14 and supplied to the supply roller 19 through the yarn path guides 16 to 18. Thereafter, the yarn 15 is heat treated by the first heater 20 while being twisted by the twisted body 23, and the structure is fixed by the cooling plate 22 through the yarn path guide 21. At this time, the tension measured between the cooling plate 22 and the twisted body 23 was taken as the twisting tension (T1), and the tension measured between the twisted body 23 and the stretching roller 24 was taken as the untwisting tension (T2). . The structure-fixed yarn 15 is supplied to the second heater 25 via the drawing roller 24, and then wound as a crimped yarn package 29 via the yarn path guides 27 and 28 via the delivery roller 26. In addition, what is necessary is just to put the 2nd heater 25 in the case where low shrinkage is essential according to a use. Moreover, what is necessary is just to arrange | position various guides, tension | tensile_strength control apparatuses, fluid processing apparatuses, oil supply apparatuses, etc. to the apparatus of FIG. 5 as needed.

  It is preferable that the temperature of the 1st heater 20 is the range of 90-150 degreeC. When the temperature of the first heater is 90 ° C. or higher, the obtained crimped yarn can be heat-set, and an excellent crimp property (CR) and shrink property (SW) can be obtained. On the other hand, when the temperature is set to 150 ° C. or lower, a crimped yarn having good mechanical characteristics and quality can be obtained without causing softening of the yarn on the first heater or reduction in strength. The temperature of the first heater 20 is more preferably 100 to 145 ° C for the above reasons, and even more preferably 110 to 140 ° C.

  Further, it is more preferable that the first heater 20 is a non-contact type because yarn breakage due to abrasion resistance can be suppressed. When a non-contact heater is used for the first heater 20, the heater temperature is preferably 150 to 350 ° C. By setting the temperature of the first heater 20 to 150 ° C. or higher, the crimping characteristics (CR) and shrinkage characteristics (SW) of the crimped yarn of the present invention can be satisfied at the same time. On the other hand, by setting it to 350 ° C. or lower, false twisting can be performed stably without breaking the yarn. Therefore, in the case of the non-contact type, the heater temperature is more preferably 160 to 330 ° C, and further preferably 170 to 300 ° C.

  Moreover, it is preferable that the speed ratio of the supply roller 19 and the drawing roller 24 in false twisting, that is, the processing magnification is 1.1 to 1.8 times. When the processing magnification is 1.1 times or more, the twisting tension (T1) in false twisting is increased, and a high twist number is given to the yarn in the first heater 20, so that the crimping property (CR) is excellent. It becomes a crimped yarn. Further, by setting the processing magnification to 1.8 times or less, stable false twisting can be performed, and a crimped yarn excellent in quality with less fluff can be obtained. The processing magnification is more preferably 1.15 to 1.7 times, still more preferably 1.2 to 1.6 times.

  Further, in applications where a low heat shrinkage rate (SW) is required in a higher order process, it is necessary to provide the second heater 25 as described above. At this time, the temperature of the second heater 25 is preferably 80 to 140 ° C. The heat shrinkage rate (SW) of the crimped yarn can be controlled by setting the temperature of the second heater and an overfeed rate (hereinafter referred to as OF rate 1) described later. Below 80 ° C., the effect is small. Moreover, by making it 140 degrees C or less, it can process stably without a thread break. At the same time, the residual torque can be kept low by optimizing the temperature of the second heater and the OF ratio 1. The temperature of the second heater is more preferably 90 to 130 ° C, and further preferably 95 to 120 ° C.

  Further, the OF ratio 1 obtained from the following formula is preferably 10 to 30%.

OF ratio 1 (%) = (V1-V2) / V1 × 100
V1: Peripheral speed of the drawing roller 24 V2: Peripheral speed of the delivery roller 26 If the OF rate is 10% or more, the thermal shrinkage rate (SW) of the crimped yarn obtained is reduced, and the dimensional stability is improved. In addition, the residual torque can be reduced, and the delayed recovery rate of the wound crimped yarn can be reduced. On the other hand, if the OF ratio is 30% or less, yarn breakage and fusion between single fibers due to contact with the heater can be prevented, and the running stability of the yarn can be improved. The OF ratio is more preferably 12 to 25%, and further preferably 15 to 20%.

  The ratio of the peripheral speed (D) of the twisted body 23 and the speed (Y) of the stretching roller 24 (hereinafter referred to as D / Y) is preferably in the range of 1.1 to 2.0. By setting D / Y to 1.1 or more, the twisting tension and the untwisting tension are well balanced, and false twisting without fuzz and yarn breakage can be performed. Moreover, by making D / Y 2.0 or less, the surface wear of the twisted body 23 is suppressed, and even in continuous operation for several hundred hours, there is no unevenness in the longitudinal direction of the yarn, shaving of yarn, fluff, yarn Untwisted false twisting is possible. D / Y is more preferably 1.15 to 1.8, and still more preferably 1.2 to 1.7.

  In addition, a belt nip type friction false twisting tool can be preferably used as the twisted body 22 for false twisting. The angle formed by doubling the angle between the belt rotation axis that is horizontal in the belt rotation direction and the yarn travel axis that is horizontal in the direction in which the yarn travels is not particularly limited. A range of 90 to 120 ° is preferable because the yarn can be efficiently twisted and the wear of the belt itself can be kept low. Furthermore, although the surface material is not particularly limited, chloropyrene rubber or nitrile butylene rubber can be preferably used. At this time, nitrile butylene rubber is more preferable from the viewpoint of durability, cost, and flexibility. Further, if the surface hardness of the belt nip type friction false twister is 60 to 80 degrees, the cross-sectional deformation of the polylactic acid can be kept low, the scraping of the yarn can be suppressed, and the wear of the belt body is also improved. A range of 65 to 75 degrees is more preferable.

  In the method for producing a crimped yarn of the present invention, the overfeed rate (hereinafter referred to as OF rate 2) of the delivery roller 26 needs to be appropriately optimized by setting the OF rate 1. When the second heater is not used and the relaxation heat treatment is not performed, the OF ratio 2 needs to be set high, and is preferably approximately 10 to 35%. Further, when the relaxation heat treatment is performed using the second heater, the OF ratio 2 is preferably 0 to 25%. The OF ratio of 2 is sufficient if the yarn can be wound stably without loosening between the delivery roller 26 and the cheese 29 so that the yarn tension is 0.02 to 0.10 cN / dtex. By winding, the delayed recovery rate of the wound yarn can be reduced, and the difference between the inner and outer layers of the physical properties of the fiber due to tightening can be reduced. In addition, the saddle and bulge are suppressed, and a package with a good winding shape can be obtained.

OF ratio 2 (%) = (V2-V3) / V2 × 100
V2: Circumferential speed of the delivery roller V3: Winding peripheral speed The crimped yarn obtained by the above-described method is process passability in a higher order process, for example, when used for knitting, a fiber and a yarn path guide, In order to suppress rubbing with a knitting needle or the like as much as possible, it is preferable to perform additional oil. As the oil to be applied, it is preferable to use an oil containing a smoothing agent having a high effect of reducing the coefficient of friction between the fibers and the metal. For example, fatty acid ester, polyhydric alcohol ester, ether ester, silicone, mineral oil and the like are preferable. These smoothing agents may be used as a single component, but a plurality of components may be mixed and used in consideration of convergence, antistatic properties, and heat resistance. As more preferred smoothing agents, fatty acid esters and mineral oils can be selected. The fatty acid ester is not particularly limited, and examples thereof include monohydric alcohols and monohydric carboxylic acids such as methyl oleate, isopropyl myristate, octyl palmitate, oleyl laurate, oleyl oleate, and isotridecyl stearate. Monohydric alcohols such as esters, dioctyl sebacate, dioleyl adipate, and esters of polyvalent carboxylic acids, polyhydric alcohols such as ethylene glycoldiolate, trimethylolpropane tricaprylate, glycerol trioleate, and monovalents Examples thereof include esters of carboxylic acids and alkylene oxide addition esters such as lauryl (EO) n octanoate. The content of these smoothing agents is adjusted to 55 to 95% by weight based on the whole oil agent, and other components include ionic surfactants, nonionic surfactants, bundling agents, rust preventives, preservatives, and antioxidants. An agent, a penetrating agent, a surface tension reducing agent, a phase inversion viscosity reducing agent, an adhesive property improving agent, an antistatic agent, a pH lowering inhibitor, and a water resistance agent may be added as appropriate.

  Hereinafter, the present invention will be described in detail with reference to examples. In addition, the measuring method in an Example used the following method.

A. Weight average molecular weight Tetrahydrofuran was mixed with the chloroform solution of the sample to prepare a measurement solution. This was measured by gel permeation chromatography (GPC), and the weight average molecular weight was determined in terms of polystyrene.

B. Intrinsic viscosity [η]
A sample polymer was dissolved in orthochlorophenol (hereinafter abbreviated as OCP), and a relative viscosity ηr at a plurality of points was determined using an Ostwald viscometer at a temperature of 25 ° C., and the outer layer was determined as an infinite dilution.

C. Melting | fusing point Melting | fusing point was measured by 2nd run using DSC-7 made from Perkin elmer. At this time, the sample weight was about 10 mg, and the heating rate was 10 ° C./min.

D. Total carboxyl terminal concentration A precisely weighed sample was dissolved in o-cresol (water content 5%), and an appropriate amount of dichloromethane was added to the solution, followed by titration with a 0.02 N KOH methanol solution. At this time, an oligomer such as lactide, which is a cyclic dimer of lactic acid, is hydrolyzed to generate a carboxyl group terminal, so that all of the carboxyl group terminal of the polymer, the monomer-derived carboxyl group terminal, and the oligomer-derived carboxyl group terminal are totaled. The carboxyl group terminal concentration obtained is obtained.

E. Residual lactide amount 1 g of a sample is dissolved in 20 ml of dichloromethane, and 5 ml of acetone is added to this solution. Furthermore, it was made to deposit with cyclohexane, it was made to precipitate, it analyzed by the liquid chromatograph using Shimadzu GC17A, and the amount of lactide was calculated | required with the absolute calibration curve.

F. Thickness of crystalline polyester film Fixed crimped yarn with embedding material, cut out sections, decapsulated, magnified with an optical microscope, photographed, and sheath thickness using a scale taken at the same magnification Was measured. In addition, when the thickness of the sheath portion was uniform, the average of three values measured at equal intervals was used, and when it was not uniform, the thinnest portion was defined as the thickness of the film of the sample.

G. Strength and elongation Measured according to the chemical fiber filament yarn test method (1998) of JIS L1013. Note that a load-elongation curve was obtained with a gripping interval of 200 mm and a tensile speed of 200 mm / min. Next, the load value at the time of breaking was divided by the initial fineness, which was taken as the strength, the elongation at the time of breaking was divided by the initial sample length, and the strength and elongation were obtained as the elongation. In addition, the temperature at the time of measurement was implemented on two conditions, room temperature (25 degreeC) and high temperature (elongation in a 90 degreeC heating furnace).

H. Boiling water shrinkage Boiling water shrinkage (%) = [(L0−L1) / L0)] × 100 (%)
L0: Raw length measured with sample taken and measured under initial load of 0.09 cN / dtex L1: Case where L0 was measured for 15 minutes in boiling water under load-free condition, air-dried for one day and night, initial load of 0 Case length under 0.09 cN / dtex Yarn spots U%
Using UT4-CX / M manufactured by Zellweger uster, U% (Normal) was measured at a yarn speed of 200 m / min and a measurement time of 1 minute.

J. Saddle and bulge ratio In a 5 kg wound package, the winding thickness L1 at the center of the undrawn yarn package and the winding thickness L2 at the end face were measured, and the value obtained by subtracting L1 from L2 was taken as the size of the saddle. Further, the winding width L3 of the innermost layer of the undrawn yarn package shown in FIG. 2 and L4 indicating the maximum winding width were measured, and the bulge rate was calculated by the following equation.

Bulge rate (%) = [(L4−L3) / L3] × 100
K. CR value The crimped yarn was scraped, treated in boiling water for 15 minutes in a substantially load-free state, and air-dried for 24 hours. The sample was immersed in water under a load equivalent to 0.088 cN / dtex (0.1 gf / d), and the skein length L0 after 2 minutes was measured. Next, the skein length L1 after 2 minutes was measured after exchanging with a fine load equivalent to 0.0018 cN / dtex (2 mgf / d), except for the case corresponding to 0.088 cN / dtex in water. And CR value was calculated by the following formula.

CR (%) = [(L0−L1) / L0] × 100 (%)
L. Delayed recovery rate (%)
After winding the yarn from the package immediately after winding by a measuring machine with a tension of 0.03 cN / dtex 20 times and applying a load, a load is applied so that it becomes 0.015 cN / dtex within 10 seconds. The casket length L3 when left for a week is measured. Next, after removing the load and letting it shrink for 24 hours, a load is applied so as to be 0.015 cN / dtex, and the casket length L4 at that time is measured. From the two casket lengths L3 and L4 thus measured, the delay recovery rate is calculated by the following equation. All the above measurements were carried out in a room temperature 25 ± 3 ° C. environment.

Delay recovery rate (%) = [(L3−L4) / L3] × 100
M.M. Expansion and contraction rate In accordance with JIS L1090 synthetic fiber filament bulk processing thread test method (1998), according to method 5.7 (C) (simple method), heat treatment is performed by the method shown in FIG. The elongation and elastic modulus were defined.

Expansion / contraction elongation (%) = [(L1-L0) / L0] × 100%
Elastic modulus of elasticity (%) = [(L1−L2) / (L1−L0)] × 100%
L0: Length of casserole after 90 ° C. hot water treatment for 20 minutes with a 1.8 × 10 ⁻³ cN / dtex load suspended from a fiber casserole and air-dried for one day and night L1: L0 measurement load is removed after L0 measurement 90 × 10 ⁻³ cN / dtex load and casket length 30 seconds later L2: After L1 measurement, remove L1 measurement load and leave for 2 minutes, then again 1.8 × 10 ⁻³ cN /
Case length after 30 seconds of hanging dtex load Residual torque The upper ends of both ends are 0.059 cN / dtex so that the crimped yarn is bent into a V shape with a ceramic rod guide as a fulcrum so that no untwisting and untwisting occur. Fix under load of. A fine load of 0.003 cN / dtex is applied to the sample portion of the rod guide, the sample is removed from the rod guide, and the sample is self-rotated in a suspended state. When the turning stopped, the twisting was carried out with a twisting machine and the number of turns was measured. The residual torque per 1 m of sample was calculated | required by making the test frequency into 5 times and doubling the average value.

O. Iron heat resistance test A sample of about 84 dtex was woven into a plain woven fabric at a weaving density of 110 × 90 pieces / inch (2.54 cm) as warp and weft, set in a living machine with a 140 ° C. tenter, and then scoured to obtain a woven fabric. This fabric was dyed at 110 ° C. for 60 minutes with a disperse dye Dianix Black BG-FS200 1% owf concentration, then 80 ° C. at a concentration of 2 g / liter of Gran Up INA-5 (manufactured by Sanyo Chemical) and 0.5 g / liter of sodium carbonate. Soaped for 20 minutes and finished at 130 ° C.

About the obtained dyed cloth, using a steam iron A-1F manufactured by Sanyo Electric Co., Ltd., when the iron surface temperature reaches a predetermined temperature, the cloth is pressed with the iron's own weight (surface pressure of about 8 g / cm ² ) for 10 seconds. The appearance change after pressing was evaluated.

  "No change" is "◎", "Slight attrition" is "○", "Clear attrition" is "△", "Partial fusion between fibers" is "X", "Melting" “Perforated” by “XX”.

P. Dyeing fastness test Dyeing cloths obtained in the same manner as in section L were subjected to class judgment according to dyeing fastness to washing JIS L0844 (1998) and dyeing fastness test to carbon arc lamp JIS L0842 (1998). .

Q. Dye fastness test against friction A dyed fabric obtained in the same manner as in section L is treated using a friction tester type II (Gakushoku type) in accordance with JIS L0849 (1998). The grade was judged in 5 stages.

Example 1
A polycarbodiimide "carbodilite" HMV-8CA manufactured by Nisshinbo Co., Ltd. as a compatibilizer in poly L lactic acid (optical purity 97% L lactic acid) having a weight average molecular weight of 16,000, a melting point of 170 ° C. and a residual lactide amount of 0.085% by weight. 1% by weight of PTT (melting point 228 ° C.) having an intrinsic viscosity [η] of 0.92 containing 0.3% by weight of titanium oxide having an average secondary particle size of 0.4 μm. As the sheath, using a spinner shown in FIG. 3 respectively melted separately, using a die apparatus having a structure shown in FIG. 4 at a spinning temperature of 250 ° C. (discharge hole diameter 0.25 mm / hole depth 0.75 mm), A core-sheath composite ratio (% by weight) was discharged at 55:45. The residence time from melting to discharging was about 18 minutes for the core component and about 11 minutes for the sheath component. The discharged yarn is cooled and solidified by a cooling chimney 7 with a cooling air of 0.5 m / second, and an oil agent is applied while being focused by an oil supply device 9 at a position 2 m below the base. The cheese package was entangled at 0.2 MPa, taken up by the first godet rolls 11 and 12 at a peripheral speed of 3000 m / min, and wound with 5 kg of 105 dtex, 36 filament core-sheath composite unstretched yarn. The peripheral speed of the winder 13 was about 2940 m / min, and the peripheral speed was varied so that the winding tension was always 0.08 cN / dtex. The surface pressure during winding was 10 kg / m, and the twill angle was 6 °. In addition, as a smoothing agent for spinning oil, 70% by weight of polyether having a weight average molecular weight of 2000, 8% by weight of polyether having a weight average molecular weight of 6000, 12% by weight of ether ester, and other additives (antistatic agent, antioxidant) Agent and rust preventive agent) were adjusted to 10% by weight, and this oil was adjusted to a concentration of 10% by weight as a water emulsion, and adhered to the fiber as a pure oil by about 0.8% by weight. The spinnability was good, and no yarn breakage occurred when sampling 50 kg of undrawn yarn. Further, the saddle of the package was 4 mm, and the bulge was 5%, which was a good foam.

  Further, the unstretched yarn is provided with a three-axis twister shown in FIG. 5 (11 sheets, first, second and eleventh counted from the yarn feeding direction are ceramic discs, and the others are urethane discs). Using a machine, stretched false twist at a processing speed of 500 m / min, a processing magnification of 1.45 times, a first heater temperature of 130 ° C. and a D / Y ratio of 1.35, followed by a second heater temperature of 120 ° C. and an OF ratio of 15%. A relaxation heat treatment was performed, and the OF rate at the delivery roller exit was set to 1%, and 84 decitex, 36 filament crimped yarn was wound up. The yarn threading property and process passability were good, and yarn breakage did not occur. The obtained yarn had a crimping property of 30% and a stretching / retracting rate (CR) of 50%, and a false twisted yarn with good mechanical properties and crimp properties was obtained. When the iron heat resistance and wear resistance of the false twisted yarn were evaluated, it had extremely excellent characteristics. The cross-sectional shape of the obtained yarn was the circular shape shown in FIG. 1 (a), and the coating thickness of the sheath portion was 1.2 μm.

  The strength of Example 1 was 2.8 cN / dtex, residual elongation 40%, U% (normal test) 0.6%, boiling water shrinkage 4.8%, delayed recovery rate 1.3%. . In addition, the stretch recovery rate (CR) indicating the crimp characteristics of the obtained yarn is 30%, the stretch elongation rate is 50%, the residual torque is 75 T / m, and exhibits extremely excellent mechanical properties and high bulkiness. It had elasticity and shape stability. Furthermore, the iron heat resistance when it was made into a woven fabric did not change its surface even at 200 ° C. and showed extremely good heat resistance. Also, in the dyeing fastness test against friction, both dryness and wetness were grade 4.

  As described above, Example 1 shows the mechanical properties of the crimped yarn and the heat resistance and wear resistance of the fabric, which are sufficiently practical and can be suitably used for clothing.

Example 2, Example 3 and Example 4
Evaluation was made in the same manner as in Example 1 except that the core-sheath composite ratio was 70/30, 80/20, and 88/12. The film thickness of Example 2 having a sheath composite ratio of 30% is 1.2 μm, the iron heat resistance does not change up to 200 ° C., and the dyeing fastness to friction is grade 4 for both dry and wet. Similarly, it showed excellent characteristics and also excellent crimp characteristics. The film thickness of Example 3 with a composite ratio of the sheath of 20% is 0.8 μm, the heat resistance of the iron does not change up to 180 ° C., and the dyeing fastness to friction is sufficient for dry grade 3 and wet grade 4 It showed heat resistance and wear resistance that could withstand practical use. The film thickness of Example 4 having a sheath composite ratio of 12% was 0.45 μm. The iron heat resistance did not change at 160 ° C., and a slight crack was observed even at 200 ° C. In addition, the dyeing fastness to friction is dry grade 3 and wet grade 4 and is lower than that of Example 1, but it is a level that can be developed for applications that do not require much wear resistance, such as inner and curtains. .

Comparative Example 1
Evaluation was made in the same manner as in Example 1 except that the core-sheath composite ratio was 92/8. The film thickness of Comparative Example 1 was 0.3 μm. Although the strength, yarn unevenness U%, etc. show good values, the iron heat resistance has some attrition at 160 ° C., and at 180 ° C., noticeable attrition occurs due to deformation of the fiber, resulting in a strong surface gloss appearance, The texture was rough. In addition, the fastness to dyeing with respect to friction was second grade for both dry and wet, and was impractical.

Comparative Example 2
Evaluation was made in the same manner as in Example 1 except that the core-sheath composite ratio was changed to 100/0 (poly L lactic acid alone). In Comparative Example 2, although the strength, yarn unevenness U%, and the like are good, in the iron heat resistance test, a partial fusion occurs at 160 ° C. to give a strong texture, and at 180 ° C. it melts and opens a hole. I have. Further, the fastness to dyeing with respect to friction was first grade for both dry and wet, and was impractical.

Example 5
Evaluation was performed in the same manner as in Example 2 except that polybutylene terephthalate (melting point 224 ° C.) having an intrinsic viscosity [η] of 0.88 was used for the sheath. In Example 5, both spinnability and drawability were good, and no yarn breakage occurred even with 50 kg of yarn. Further, the strength and the yarn unevenness U% were good, but the crimp characteristics were slightly inferior to those of Example 2. Moreover, the iron heat resistance did not change up to 180 ° C., and the fastness to dyeing with respect to friction was dry grade 3 and wet grade 4, indicating heat resistance and wear resistance that could withstand practical use.

Example 6
Evaluation was performed in the same manner as in Example 2 except that copolymerized PET (melting point: 230 ° C.) containing 9 mol% of IPA in the sheath was used. In Example 6, both spinnability and drawability were good, and no yarn breakage occurred even with 50 kg of yarn. Further, the strength and the yarn unevenness U% were good, but the crimp characteristics were slightly inferior to those of Example 2, and the boiling water shrinkage rate was high. The iron heat resistance did not change up to 180 ° C., and the dyeing fastness to friction was dry grade 3 and wet grade 4;

Example 7
Evaluation was performed in the same manner as in Example 2 except that DuPont biodegradable polyester “Biomax” 4027 (melting point: 237 ° C.) was used for the sheath. In Example 6, both spinnability and drawability were good, and no yarn breakage occurred even with 50 kg of yarn. Moreover, although intensity | strength and thread spot U% were favorable, since the bulkiness and the elasticity were inferior, the use was limited. The iron heat resistance did not change even at 200 ° C., and the dyeing fastness to friction was dry grade 3 and wet grade 4 and showed heat resistance and wear resistance that could withstand practical use.

Comparative Example 3
Evaluation was performed in the same manner as in Example 2 except that DuPont biodegradable polyester “Biomax” 4024 (melting point: 199 ° C.) was used for the sheath. In Comparative Example 3, both spinnability and stretchability were good, and no yarn breakage occurred even with 50 kg of yarn. Further, the strength and the yarn unevenness U% were also good. However, in the iron heat resistance test, the appearance became strong with surface gloss at 160 ° C., and the practicality was poor.

Example 8
Poly L-lactic acid (optical purity 97% L lactic acid) having a weight average molecular weight of 16,000, a melting point of 170 ° C. and a residual lactide amount of 0.085% by weight, and a poly D lactic acid having a weight average molecular weight of 200,000 (used in Example 2) Chip blending with optical purity 97% D lactic acid, melting point 170 ° C. at a weight ratio of 1: 1, melt-kneading at 240 ° C. with a twin screw extrusion kneader, and then a static kneader (Toray Engineering) installed in the spinning machine It was evaluated by the same method as in Example 2 except that it was led to a spinning pack after passing through “High Mixer” (10 stages) and used as a core component (no compatibilizer added). In the sample of Example 8, the melting point of the double peak was detected by DSC. One is a peak near the melting point of 228 ° C., so that it is a melting peak of the PTT crystal, and the other is presumed to be a melting peak of a stereocomplex crystal of polylactic acid having a melting point of 220 ° C. In addition, although Example 8 was slightly lower in strength than Example 2, it exhibited excellent characteristics in terms of crimp characteristics, iron heat resistance, and fastness to staining.

Example 9
Evaluation was made in the same manner as in Example 2 except that no compatibilizing agent was contained in the core component. In Example 8, some cracks occurred in the iron heat resistance test at 200 ° C. Further, although the wear resistance was slightly inferior to that of Example 2, it was at a level causing no practical problem.

Example 10
Polycarbodiimide "Carbodilite" manufactured by Nisshinbo Co., Ltd. as a compatibilizer in poly L lactic acid (optical purity 91% L lactic acid) having a weight average molecular weight of 16,000, melting point of 155 ° C and residual lactide amount of 0.15% by weight as the core component The same method evaluation as in Example 2 was performed except that 1% by weight of HMV-8CA was added and mixed to form core A. The sample of Example 10 had a slight attack in the iron heat resistance test at 160 ° C., but a clear attack occurred at 180 ° C. and 200 ° C., and ironing at a high temperature was not possible. It was. The mechanical properties and crimp properties of the crimped yarn were slightly inferior to those in Example 2, but the wear resistance was excellent as in Example 2.

Example 11
PTT (melting point 227 ° C.) having an intrinsic viscosity [ηr] of 1.35 (weight average molecular weight 85,000) containing 0.3% by weight of titanium oxide having an average secondary particle size of 0.4 μm as the sheath component was used. Except for the above, evaluation was performed in the same manner as in Example 2. Although Example 11 was excellent in crimp characteristics, compared with Example 2, the strength was low and the yarn unevenness U% was also large. The 200 ° C. iron heat resistance test produced some cracks and the wear resistance was slightly inferior to that of Example 2.

Comparative Example 4
Evaluation was made in the same manner as in Example 2 except that the first heater temperature in false twisting was 75 ° C.

  Comparative Example 4 was excellent in mechanical properties and had practical levels of both iron heat resistance and wear resistance, but had a low expansion / contraction recovery rate of 9% and almost no bulkiness.

Comparative Example 5
Evaluation was performed in the same manner as in Example 2 except that the second heater was not passed through false twisting and the OF ratio 1 was set to 0% (constant length). In Comparative Example 5, the delayed recovery rate was high by 6.7%, so that the wound cheese package was deformed by tightening and the unwinding property was poor. In addition, the mechanical properties, iron heat resistance, and wear resistance were practical levels, but the paper has a feeling of coarseness when made into a woven fabric due to its high boiling water shrinkage rate of 22% and low bulk height. I only got something like.

Example 12
Evaluation was performed in the same manner as in Example 2 except that the processing magnification in false twisting was set to 1.60 times. Example 12 showed excellent mechanical properties and bulkiness. However, since the residual torque was as high as 205 T / m, the production of a woven fabric using the crimped yarn as a single yarn would cause skewing. It was limited to thread use.

Example 13
Evaluation was performed in the same manner as in Example 2 except that the pipe diameter in the spinning pack was changed and the residence time of the core component was 40 minutes. In Example 13, although the iron heat resistance and wear resistance were excellent, the color tone of the raw machine was slightly strong in yellow, and the b ^* value in the L ^* a ^* b ^* color system was also 5.2. Moreover, the color tone after dyeing was dull, inferior to Example 2 in terms of sharpness, and limited in color for clothing.

Example 14
The same as Example 2 except that the first godet roll and the second godet roll were set to a circumferential speed of 1000 m / min, the winding speed was 995 m / min, and the undrawn yarn configuration was 174 dtex and 36 filaments. According to spinning conditions. Further, false twisting was performed under the same conditions as in Example 2 except that the unstretched yarn was set to a processing magnification of 2.4 times to obtain a crimped yarn of 84 dtex and 36 filaments. In Example 14, thread breakage frequently occurred because the processing tension during false twisting was not stable. Further, the obtained yarn was inferior to Example 2 in terms of mechanical properties, crimp properties, iron heat resistance, and wear resistance, and its use was only limited.

Example 15
Example 1 except that the first godet roll and the second godet roll were set at a peripheral speed of 2000 m / min, and the winding speed was set at 1970 m / min so that the unstretched yarn had a configuration of 130 dtex and 36 filaments. According to spinning conditions. Further, the undrawn yarn was false twisted at a processing magnification of 1.8 times to obtain a crimped yarn of 84 dtex and 36 filaments. The sample of Example 15 was superior to Example 14 in both mechanical properties and crimping properties, and both iron heat resistance and wear resistance were at a level with no practical problems.

Example 16
Example 1 except that the first godet roll and the second godet roll were rotated at a peripheral speed of 4000 m / min, the winding speed was 3900 m / min, and the structure of the undrawn yarn was 98 dtex and 36 filaments. According to spinning conditions. Further, the undrawn yarn was false twisted at a working magnification of 1.35 times to obtain a crimped yarn of 84 dtex and 36 filaments. As in Example 2, the sample of Example 16 exhibited excellent characteristics in all of the mechanical characteristics, crimp characteristics, iron heat resistance, and wear resistance.

Example 17
The same as Example 2 except that the first godet roll and the second godet roll were set to a peripheral speed of 5000 m / min, and the winding speed was 4875 m / min, so that the undrawn yarn configuration was 90 dtex and 36 filaments. According to spinning conditions. Further, the undrawn yarn was false twisted at a working magnification of 1.25 times to obtain a crimped yarn of 84 dtex and 36 filaments. The sample of Example 17 had excellent mechanical properties, crimp characteristics, and wear resistance, as in Example 2, although the yarn unevenness U% was 1.5%, which was slightly worse. Further, the iron heat resistance was sufficiently practical at 200 ° C., although there was some damage.

It is a figure which shows the fiber cross-sectional shape of the composite yarn preferably used by this invention. It is the schematic for demonstrating the saddle and bulge rate of a cheese-like package. 1 is a schematic view of a spinning device preferably used in the present invention. It is a longitudinal cross-sectional view of a die preferably used for producing the composite yarn of the present invention. It is the schematic of the false twist processing apparatus preferably used by this invention. It is the schematic for demonstrating the measuring method of expansion-contraction elongation rate.

Explanation of symbols

1: A component hopper 1 ': B component hopper 2: A component extrusion kneader (extruder)
2 ': B component extrusion kneader (extruder)
3: Metering pump 4: Spinning block 5: Spin pack 6: Base 7: Cooling device 8: Thread 9: Refueling guide 10: Entangling device 11: First godet roller 12: Second godet roller 13: Winder 14: Winding yarn package 15: Yarn 16: Yarn path guide 17: Yarn path guide 18: Yarn path guide 19: Supply roller 20: First heater 21: Yarn path guide 22: Cooling plate 23: Twist 24: Drawing roller 25: second heater 26: delivery roller 27: yarn path guide 28: yarn path guide 29: crimped yarn package

Claims (7)

In a multifilament composed of a core-sheath composite fiber of 3 filaments or more, the thermoplastic resin forming the core part A of the core-sheath composite fiber is aliphatic polyester, and the thermoplastic resin forming the sheath part B has a melting point of 200 ° C. or higher. A crimped yarn excellent in heat resistance, characterized in that the film thickness of the crystalline polyester and the crystalline polyester forming the sheath part B is 0.4 μm or more and satisfies the following characteristics at the same time.
Expansion and contraction rate (CR): 10-50%
Boiling water shrinkage (SW): 2 to 20%   2. The crimped yarn excellent in heat resistance according to claim 1, wherein the aliphatic polyester forming the core A is polylactic acid.   The crimped yarn excellent in heat resistance according to claim 1 or 2, wherein the crystalline polyester forming the sheath part B is polytrimethylene terephthalate.   The crimped yarn excellent in heat resistance according to any one of claims 1 to 3, wherein the total carboxyl terminal concentration of the composite fiber is 20 equivalent / ton or less.   5. A crimped yarn excellent in heat resistance according to any one of claims 1 to 4, wherein a delayed recovery rate is 5% or less.   The crimped yarn excellent in heat resistance according to any one of claims 1 to 5, wherein the stretch elongation rate is 15 to 100%.   A fiber structure using at least a part of the crimped yarn according to any one of claims 1 to 6, wherein in a fastness test against friction (friction tester type II), a dry grade 3 or higher, a wet 3 A dyed fiber structure having a dyeing fastness of a grade or better.

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